Electromechanical structure and method of making same

ABSTRACT

An electromechanical structure includes a core and a plurality of conductive pins through the core. The pins are configured to form a signal distribution network from a first side of the core to a second side of the core.

RELATED APPLICATIONS

This application claims the benefit of and priority to U.S. ProvisionalApplication No. 60/704,089, filed Jul. 29, 2005, which is herebyincorporated herein by reference.

FIELD OF THE INVENTION

This subject invention relates to a dual function composite system andelectromechanical structures, and in one example, multilayer printedcircuit boards which can replace conventional printed circuit boards.

BACKGROUND OF THE INVENTION

Composite technology offers a wide variety of advantages including ahigh strength to weight ratio. Thus, composite systems are now used inmobile platforms such as aircraft and spacecraft for a variety ofstructural components.

Those skilled in the art are also studying higher and more complexlevels of system integration. In but one example, it would be useful tointegrate antennas into composite aircraft wing panels or other aircraftstructures such as a panel of a fuselage or a portion of a door, or toapply or attach antennas to an aircraft. Current design challengesinclude how to provide sufficient dielectric separation between theradiating antenna elements and the ground plane of the antenna. Platedthrough hole printed circuit board technology cannot be used inconnection with such advanced systems due to the inability to form viastructures in lightweight dielectric materials (e.g. open cell foams),and/or the inability to form very high aspect ratio vias in dielectricmaterials. Also, it would be desirable to integrate the electrical busextending between the antenna and this electronic subsystem into theaircraft structure. Otherwise, the weight savings provided by compositetechnology will suffer and the cost of using composite technology willbe prohibitive.

SUMMARY OF THE INVENTION

It is therefore an object of this invention to provide composite systemswith integrated electrical subsystems.

It is a further object of this invention to provide, in one embodiment,a notional antenna fully integrated with a composite aircraft wingpanel.

It is a further object of this invention to provide such an integratednotional antenna which also includes a bus integrated with compositeaircraft structural members.

It is a further object of this invention to provide, in compositestructures, signal transmission pathways through the thickness of thecomposite and running in the plane of the composite.

It is a further object of this invention to provide a functionalreplacement for a plated through hole in a printed circuit board whenmaterials and/or geometries prevent a plated through hole from beingformed.

The subject invention results from the realization that, given a threedimensional composite system, electrical pathways in one direction canbe established by inserting conductive pins to extend through thecomposite panel and an electrical pathway in the direction of the planeof the panel can be affected by integrating conductors into a ply of acomposite component. The invention results from the further realizationthat when plated through holes or vias in a printed circuit board arenot possible, conductive pins may replace them as electrical pathways.

The subject invention, however, in other embodiments, need not achieveall these objectives and the claims hereof should not be limited tostructures or methods capable of achieving these objectives.

This invention features an electromechanical structure including a coreand a plurality of conductive pins through the core. The pins areconfigured to form a signal distribution network from a first side ofthe core to a second side of the core. In one embodiment, there is anarray of radiating elements on the first side of the core each connectedto one end of a pin, and a printed circuit board on a second side of thecore electrically connected to the other ends of the pins forming anotional antenna subsystem. In one configuration, the electromechanicalstructure further includes a composite member which includes plies offabric and resin impregnating the plies of fabric and at least one plyincludes signal transmission elements integrated therewith and connectedbetween the printed circuit board and electronics for the notionalantenna system. The core may be a dielectric, and the dielectric coremay be air. In such an example, the dielectric core will typicallyinclude a dielectric support mechanism which may be a dielectrichoneycomb structure, or a dielectric truss structure for example. Such adielectric truss structure may include a network of dielectric pinsforming the truss structure. The dielectric core also may be a lowdensity material, preferably foam, or the dielectric core may be apolymer. In one example, the structure includes a radome layer over theradiating elements, which may be made of astroquartz. In one preferredembodiment, a ground plane is disposed between the core and the printedcircuit board, and the ground plane may be a composite layer includingplies of conductive fibers impregnated with a resin, and the fibers maybe carbon. The structure may further include a structural layer betweenthe ground plane and the printed circuit board, and the structural layermay include a foam sub-layer on a composite sub-layer. The compositesub-layer may include fibers impregnated with a resin, and the compositesub-layer fibers may be carbon. Typically, the ground plane includesholes therethrough for conductive pins. The conductive pins may beinsulated and/or the holes may provide clearance between the conductivepins and the ground plane. Preferably, the pins are solid and made of ametal alloy, which may include copper. In another configuration, thepins include a composite core surrounded by metal coating. In a furtherconfiguration, the pins include a central conductor surrounded by adielectric material surrounded by a coaxial shield conductor. In anothervariation the pins may be tubular, and in one configuration some pinsmay be configured to provide sidewall metallization around a cavity ofradiating element.

The radiating elements may be printed on the core. The pins may beinserted through holes drilled in the core, or the pins may first beinserted through the holes formed in the dielectric core and theradiating elements then printed over the pins. The signal transmissionelements are preferably wires which may be woven into the at least oneply of the composite member, and the wires may be insulated. In oneexample, the core is a solid composite component made of a number ofplies of fabric impregnated with a resin.

This invention also features an electromechanical structure including alow density dielectric core, an array of radiating elements one side ofthe core, and a printed circuit board on an opposing side of the core.There are a plurality of conductive pins through the core and insulatedtherefrom. The pins are configured to form a signal distribution networkfrom the radiating elements to the printed circuit board.

This invention further features a method of fabricating anelectromechanical structure, the method including inserting a pluralityof conductive pins through a core and configuring the pins to form asignal distribution network from a first side of the core to a secondside of the core. In one embodiment there is an array of radiatingelements on the first side of the core each connected to one end of apin and a printed circuit board on a second side of the coreelectrically connected to the other ends of the pins forming a notionalantenna subsystem. In one configuration, the method further includes theaddition of a composite member, which itself includes plies of fabricand resin impregnating the plies of fabric. At least one ply includessignal transmission elements integrated therewith and connected betweenthe printed circuit board and electronics for the notional antennasystem. The core is typically a dielectric, and it may be air, in whichcase the dielectric core will typically include a dielectric supportmechanism. The dielectric support mechanism may be a dielectrichoneycomb structure, or the dielectric support mechanism may be adielectric truss structure, which may include a network of dielectricpins forming the truss structure. The dielectric core may be a lowdensity material, preferably foam, or the dielectric core may be ahoneycomb structure. In one example, the method further includesdisposing a radome layer over the radiating elements, which may be madeof astroquartz. A ground plane may be disposed between the core and theprinted circuit board, in which the ground plane is a composite layerincluding plies of conductive fibers impregnated with a resin, and thefibers are carbon. The method may further include disposing a structurallayer between the ground plane and the printed circuit board, and thestructural layer may include a foam sub-layer on a composite sub-layer.The composite sub-layer may include fibers impregnated with a resin, andthe composite sub-layer fibers may be carbon. The method may furtherinclude drilling holes therethrough for the conductive pins, and theconductive pins may be insulated. The holes may also provide clearancebetween the conductive pins and the ground plane. Preferably, the pinsare solid and made of a metal alloy which may include copper. In onevariation, the pins include a composite core surrounded by metalcoating. In another variation, the pins include a central conductorsurrounded by a dielectric material surrounded by a coaxial shieldconductor. The pins may be tubular, and in one variation, the pins maybe configured to provide sidewall metallization around a cavity of aradiating element.

The method may further include printing the radiating elements on thecore, and inserting the pins through holes drilled in the core. In onevariation, the pins may be first inserted through the holes formed inthe dielectric core and the radiating elements then printed over thepins. The signal transmission elements may be wires woven into the atleast one ply of the composite member, and the wires may be insulated.Also, the core may be a solid composite component made of a number ofplies of fabric impregnated with a resin.

This invention also features a method of fabricating anelectromechanical structure, the method including inserting a pluralityof conductive pins through a low density dielectric core and insulatingthe pins from the low density dielectric core and a ground plane. Themethod further includes disposing an array of radiating elements oneside of the core, disposing a printed circuit board on an opposing sideof the core, and configuring the pins to form a signal distributionnetwork from the radiating elements to the printed circuit board.

This invention further features an electromechanical structure includinga core, a plurality of conductive pins through the core, the pinsconfigured to form a signal distribution network from a first side ofthe core to a printed circuit board on a second side of the core. In onepreferred embodiment, there is a ground plane between the core and theprinted circuit board, and the ground plane is a thin layer between thecore and the printed circuit board. The thin layer may be copper, andthe core is typically a dielectric core. In one example, there is anarray of radiating elements on the first side of the core each connectedto one end of a pin, and the printed circuit board is electricallyconnected to the other ends of the pins forming a notional antennasubsystem. The notional antenna subsystem may be configured to beaffixed to an aircraft panel, in one example. The dielectric core may beair, and in such a case the dielectric core will typically include adielectric support mechanism. The dielectric support mechanism may be adielectric honeycomb structure, or the dielectric support mechanism maybe a dielectric truss structure. The truss structure may include anetwork of dielectric pins forming the truss structure. The dielectriccore may also be a low density material, preferably foam. The dielectriccore may also be a polymer. There may be a radome layer over theradiating elements, and it may be made of astroquartz. The ground planemay include holes therethrough for the conductive pins. The conductivepins may be insulated, and/or the holes may provide clearance betweenthe conductive pins and the ground plane. The pins may be solid and madeof a metal alloy including copper or the pins may include a compositecore surrounded by metal coating. In other examples, the pins include acentral conductor surrounded by a dielectric material surrounded by acoaxial shield conductor, or the pins may be tubular. Also, some of thepins may be configured to provide sidewall metallization around a cavityof radiating element. Radiating elements may be printed on the core andthe pins inserted through holes drilled in the core, or the pins may befirst inserted through the holes formed in the dielectric core and theradiating elements are then printed over the pins.

This invention also features a method of fabricating anelectromechanical structure, the method including pre-drilling pilotholes in a dielectric core, pre-forming pilot holes in a ground plane,pre-drilling holes in a printed circuit board, and inserting a pluralityof conductive pins through each of the printed circuit board, the groundplane, and the dielectric core to bond together the dielectric core,ground plane and printed circuit board.

This invention further features a method of fabricating anelectromechanical structure, the method comprising pre-drilling pilotholes in a ground plane attached to a printed circuit board, bonding theground plane and printed circuit board to a dielectric core, drillingholes through the printed circuit board and dielectric core coincidingwith the pre-drilled pilot holes in the ground plane, and inserting aplurality of conductive pins through each of the printed circuit board,the ground plane, and the dielectric core.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features and advantages will occur to those skilled inthe art from the following description of a preferred embodiment and theaccompanying drawings, in which:

FIG. 1 is highly schematic three-dimensional view showing an example ofa composite system with an integrated electrical subsystem in accordancewith the subject invention;

FIG. 2 is a schematic three-dimensional top view of a fighter aircraftincluding a wing section with an integrated antenna array in accordancewith the subject invention;

FIG. 3 is a schematic three-dimensional cutaway side view showing aportion of the wing of FIG. 2;

FIG. 4 is a schematic side cross-sectional view of the wing structureshown in FIG. 3;

FIG. 5 is a highly schematic three-dimensional view of one embodiment ofa dielectric support mechanism for use with the subject invention;

FIG. 6A-6B are highly schematic views of another embodiment of adielectric support mechanism for use with the subject invention;

FIG. 7 is a highly schematic representation showing how individualinsulated wires can be woven with the fabric of a ply of a compositestructure in accordance with the subject invention;

FIG. 8 is a schematic three-dimensional cut-away view showing oneembodiment of a radar tile assembly for a notional antenna integrated aspart of a panel of the wing structure of FIG. 3;

FIG. 9A is a schematic cross-sectional view of an example of one type ofpin useful as a transmission element in accordance with the subjectinvention;

FIG. 10A is a schematic cross-sectional view showing another example ofa transmission pin in accordance with the subject invention;

FIG. 11A is a schematic cross-sectional view of still another embodimentof a transmission pin in accordance with the subject invention;

FIG. 12A is a schematic cross-sectional view of yet another embodimentof a transmission pin in accordance with the subject invention;

FIGS. 9B-12B are schematic views showing the pin examples of FIGS. 9-12insulated;

FIG. 13 is a schematic three-dimensional cut-away view showing anotherembodiment of a radar tile assembly for a notional antenna integrated aspart of the top panel of the wing structure shown in FIG. 3;

FIG. 14 is a three-dimensional cut-away view of a multi-layer printedcircuit board without plated through holes shown as part of another formof a notional antenna in accordance with the present invention;

FIG. 15 is a schematic three-dimensional front view showing one examplehow transmission or feed pins are inserted into a foam body inaccordance with the subject invention;

FIG. 16 is a schematic three-dimensional front view showing one examplehow radiator patches are deposited on the foam body of FIG. 15 over thepins;

FIG. 17 is a schematic three-dimensional front view showing one exampleof fabrication of a multi-layer printed circuit board for power andsignal re-distribution for the panel of the aircraft wing structureshown in FIG. 3;

FIG. 18 is a schematic three-dimensional front view showing one examplehow the flex circuit of FIG. 17 is bonded to the foam panel of FIG. 16in accordance with the subject invention;

FIG. 19 is a schematic view of one example of a fabrication process inaccordance with the present invention;

FIGS. 20-24 are schematic views of another example of a fabricationprocess in accordance with the present invention;

FIG. 25 is a schematic three-dimensional side view of anelectromechanical tile test structure in accordance with the subjectinvention;

FIG. 26 is a highly schematic three-dimensional front view of an exampleof the dual function composite and electrical system in accordance withthe subject invention; and

FIG. 27 is a schematic top view of conductive pins configured in oneexample for sidewall metallization around a cavity of a radiatingelement in accordance with one embodiment of the subject invention.

DISCLOSURE OF THE PREFERRED EMBODIMENT

Aside from the preferred embodiment or embodiments disclosed below, thisinvention is capable of other embodiments and of being practiced orbeing carried out in various ways. Thus, it is to be understood that theinvention is not limited in its application to the details ofconstruction and the arrangements of components set forth in thefollowing description or illustrated in the drawings. If only oneembodiment is described herein, the claims hereof are not to be limitedto that embodiment. Moreover, the claims hereof are not to be readrestrictively unless there is clear and convincing evidence manifestinga certain exclusion, restriction, or disclaimer.

FIG. 1 illustrates a simplified view of a three-dimensional compositesystem 10 including composite members 12 and 14. Composite member 12typically includes face sheets 16 and 18 separated by core 20. Facesheets 16 and 18 may be fabricated from plies of fabric impregnated withresin. Core 20 may be a lightweight cellular material, e.g. foam, orair. Composite member 14 includes numerous plies of fabric impregnatedwith resin.

One goal of the subject invention is to route signals from electronicsubsystem A through composite system 10 to electronic subsystem B.Conductive pin 24 is shown extending through the thickness of compositemember 12 to provide signal routing in one direction through thethickness of the composite member and wire 26 is shown integrated withthe fabric of one ply of composite member 14 to provide signal routingin another direction mainly in the plane of composite member 14. Byusing multiple pins in composite member 12 and multiple wires integratedwith one or more plies of the composite member 14, multiple electricalpathways and/or a bus can be established between subsystems A and B.

In accordance with the present invention, aircraft 32, FIG. 2 includesan integrated notional antenna electrically interconnected with anelectronic subsystem within aircraft 32. The integrated notional antennacan be located on any portion of a mobile platform such as an aircraft,for example, on the panel of an airplane fuselage or portion of a door.As shown, the integrated notional antenna is included in wing portion orpanel 30 of aircraft 32.

Wing portion 30 is shown in more detail in FIGS. 3-4. Composite lowerwing surface 34 includes an integrated array of radiating elements 36.Elements 36 may be rectangular, circular or elliptical with dimensionson the order of 0.1 inches by 0.1 inches up to several inches by severalinches depending on the radar operating frequency. The separationbetween the centers of elements 36 can be or the order of 0.25 inches toseveral feet.

Integrated wires 26 may be included in any suitable structural membersuch as an aircraft fuselage, door, or portion of a wing. In onepreferred configuration, composite spar 38 includes integrated wires 26for connecting the antenna subsystem to its associated electronicspackage and for providing support for the aircraft wing panel. As shownmore clearly in FIG. 4, the notional antenna subsystem includes an arrayof radiating elements 36 separated from ground plane 40 by core 42 oflow density or lightweight cellular material, or air, serving as astandoff dielectric. The dielectric may be any polymer, foam (open cellor closed cell), or in the case where core 42 is air, structuralintegrity is maintained by a dielectric support mechanism 11, FIGS. 5and 6A-6B. One embodiment of such a dielectric support mechanism 11 ishoneycomb structure 13, FIG. 5, which may be made up of plastic,thermoplastic polymer, e.g., liquid crystal polymer or LCP, Kevlar,aramid, or other known materials. In another example, structural supportcan be provided by a dielectric support mechanism 11 including a networkof dielectric pins 15 configured as truss structure 17, FIGS. 6A-6B. Oneexample of such a structure is discussed in U.S. Pat. No. 6,291,049which is incorporated herein by reference. Dielectric pins 15 aretypically non-conductive material such as ceramic, glass, polymer orother known material. The size, number, and angles of dielectric pins 15may be varied depending on a particular desired application.

In one preferred embodiment, the radiating elements 36, FIG. 4 areseparated from ground plane 40 by dielectric open cell foam core 42 madeof polyetherimide or polymethacrylimide with a thickness in the rangebetween approximately several thousandths of an inch to several inchesdepending a particular application or design operating frequency.Conductive pins 24 extend through the core and each one is connected onone end to a radiating element 36. The other ends of the pins areelectrically connected to printed circuit board 44 which is connected asshown at 46 to wires 26 integrated (e.g., woven, knitted or braided)with the fabric of one ply of composite spar 38. Cover or radome layer48 is shown over radiating elements 36, typically to decreaseaerodynamic drawbacks and to protect radiating elements 36. Layer 48 ispreferably made of astroquartz or glass, but may be made of any materialwhich is effectively transparent at appropriate frequencies of radaroperations. In the case of placement on an airplane wing, such materialwill typically possess load-bearing characteristics to withstandenvironmental stresses encountered along the wing of an aircraft.Typically, ground plane 40 is a composite structure including plies ofconductive (e.g., carbon) fiber impregnated with a resin such as Cytec977-3 or Hexel M73. Optional structural layer 50 includes structuralfoam sub-layer 52 and composite sub-layer 54.

FIG. 7 shows one internal ply of composite spar 38, FIG. 4 whereinsulated wires or cables 26 are interwoven, with fabric threads 56. Inone example, spar 38 includes a textile impregnated with a resin. Seealso U.S. Pat. No. 6,727,197 incorporated herein by this reference.Alternatively, wires 26 may be woven or knitted with fabric threads 56.

FIG. 8 shows in more detail multilayer printed circuit board 44 withback side transmit and receive components 60 and back sideredistribution layers 62. Foam layer 42 forms a dielectric standoff.Sub-layer 52 in combination with ground plane 40, itself typicallyincluding carbon fibers, and carbon fiber composite sub-layer 54,provide mechanical strength and stiffness and provide a suitableload-bearing structure where lightweight, high structural strength andrigidity are important considerations. Similarly to core 42, sub-layer52 may include a honeycomb structure, truss structure, or low densitymaterial, and like core 42, is preferably foam in one embodiment.Sub-layer 52 may have a thickness in the range of between approximately0.25 inches and 2 inches, and sub-layer 54 together with ground plane 40may have a thickness in the range of between approximately 0.06 inchesand 0.10 inches. In one preferred embodiment, foam layer 42 isapproximately 0.10 inches thick, sub-layer 52 is approximately 0.25inches thick, and sub-layer 54 together with ground plane 40 isapproximately 0.10 inches thick. Pins 24 provide feeds to radiatingelements 36 from a metallurgical connection with a backside pad as shownat 63. Such a high aspect ratio hybrid structure is not generallyachievable with conventional printed circuit board manufacturingtechniques.

In one example, pin 24, FIG. 9A may be solid metal alloy made of copperand beryllium and be between approximately 0.005 inches and 0.062 inchesin diameter. There are typically 1-2 pins per radiating element.

In another embodiment, pin 24′, FIG. 10A includes composite core 70surrounded by metal coating 72 such as nickel/gold. In still anotherembodiment, coaxial pin 24″, FIG. 11 A includes central conductor 74surrounded by dielectric 76 itself surrounded by a coaxial shield 78made of conductive material to isolate central conductor 74 from anyexternal electrical radiation. Alternatively, pin 24′″, FIG. 12A istubular and made of metal alloy such as copper and beryllium. In anyconfiguration, pins 24-24′″ may be insulated. Pilot holes drilled incircuit board 44, FIG. 8 enable small diameter pins to be inserted tominimize use of circuit board area for pin interconnects. The pilotholes can be undersized for a slight press fit with the individual pins.Although pins 24 are shown herein as extending vertically, this is not anecessary limitation of the invention, and pins 24 may be oriented at anangle as desired for a particular application. Also, although pins 24are preferably electrical conductors, this is not a limitation of theinvention. In one configuration, the pins may be optical fibers forconnecting the systems.

In the embodiment of FIG. 8, ground plane 40 abuts pins 24, andtherefore pins 24 in multilayer printed circuit board 44 are preferablyinsulated to prevent electrical contact with ground plane 40. In oneexample, pins 24 are isolated from the ground plane by non-conductiveinsulating material 77. Insulation 77 may surround pin types 24, 24′,24″, and 24′″ as desired for a particular application as shown in FIGS.9B-12B. Insulation 77 may be polymer, glass, ceramic, Kevlar,fiberglass, or any other non-conductive material.

In another embodiment, multilayer printed circuit board 44, FIG. 13 doesnot include structural layer 50, FIG. 4, however, ground plane 40including plies of carbon fiber impregnated with resin providesstructural support. Since ground plane 40 abuts pins 24, insulated pins24 are preferred.

In a further embodiment, ground plane 40′, FIG. 14 of multilayer printedcircuit board 44′ forms a thin top layer over the printed circuit board61 including backside redistribution layers 62. In one example, groundplane 40′ is a copper metal layer typically between 0.0003 inches and0.003 inches thick. Although minimal to no structural support isprovided, due to its light and flexible nature, in one examplemultilayer printed circuit board 44′ may serve as another type ofnotional antenna which can be affixed to an aircraft by attaching orhanging it rather than forming an integral portion of the aircraftstructure. In a preferred configuration, ground plane 40′ includesclearance holes 68 therethrough for conductive pins 24 so the pins donot contact the ground plane. In this case, pins 24 may be insulated ornon-insulated as desired.

Accordingly, the subject invention provides composite systems withintegrated electrical subsystems, in one example notional antennas, andin various embodiments, further provides an improved alternative toplated through holes where material types or other parameters such ashigh aspect ratio prohibit the use of conventional boards.

In one embodiment, fabrication begins by inserting feed pins 24 in foampanel 42, FIG. 15. The pins can be inserted manually with or withoutpilot holes drilled in foam panel 42, inserted using an ultrasonic horn,and/or inserted using numerical control processes. Next, radiatorelements 36 are direct metal deposited on foam panel 42, FIG. 16. Aprotective layer (not shown) such as LCP, epoxy glass, or the like or abonding film or layer or metamaterials may be used to bond the elements36 to panel 42. The radiator elements make metallurgical contact withthe pins 24 previously inserted in foam panel 42. Alternatively, adirect printing technique can be used to create a radiator elementpattern, or patched radiator elements could be formed on a flex circuitfilm bonded to foam panel 42.

Next, the multilayer printed circuit board is fabricated as shown inFIG. 17 to include copper ground plane 40, clearance holes 68, power anddistribution circuitry as shown at 90 all on a multilayer flex circuitboard. The multilayer flex circuit board may include a flexiblesubstrate such as polyimide, LCP, or foam. This multilayer printedcircuit board provides power and signal redistribution and backsidecomponent attachment for MMICs and the like, and one example of theresultant multi-layer printed circuit board is board 44′, FIG. 14, wherepins 24 are uninsulated.

Thus, this flex circuit is bonded to the foam panel as shown in FIG. 18.Solder reflow techniques are used to electrically interconnect theradiator feeds provided by pins 24 to the flex circuit. The solder isreflowed to complete the metallurgical connection of the pad to pin onthe back side. In one variation, a conductive polymer such as conductiveepoxy could be used in place of solder.

In another embodiment, fabrication begins by pre-drilling pilot holes71, FIG. 19 in foam core 42 and pre-drilling pilot holes 73 in printedcircuit board 61 which typically includes redistribution portion 62.Pilot holes 75 are formed in ground plane 40 and sub-layers 52 and 54typically by using an ultrasonic horn using known ultrasonic techniques.Next, feed pins 24 are inserted through printed circuit board 61,sub-layers 52 and 54, ground plane 40, and core 42 from backside 67,thus bonding the various layers together and forming anelectromechanical structure, i.e. a multi-layer printed circuit board,and in one example, the resultant multi-layer circuit board may be board44, FIG. 8, after inclusion of metallurgical elements, antenna elements,and the like as desired for a particular application.

A further embodiment is shown in FIGS. 21-24, where fabrication beginsby pre-drilling pilot holes 80, FIG. 21 in ground plane 40 which is athin top layer over printed circuit board 61 including redistributionportion 62. Next, foam core 42 is attached to ground plane 40 andprinted circuit board 61 and ground plane 40 are drilled, FIG. 22, andpins 24 are then inserted through each of the printed circuit board 61,the ground plane 40, and the foam core 42, FIG. 23. Next, metallurgicalconnections 63, FIG. 24 can be formed as shown, and antenna elements 36may be direct deposited or printed on core 42 as discussed above. Ineach variation, the resulting electromechanical structure is capable ofbeing used in place of printed circuit boards with plated through holesfor particular desired applications as discussed above.

FIG. 25 shows one electromechanical test tile structure 100 manufacturedin accordance with this invention where electrical pathways are formedbetween path 102 on each face plate 104 a and 104 b on foam core 106. Inthis way, as shown in FIG. 26, a wide variety of electricalinterconnections could be formed to provide signal transmission betweenpoint 110 on face sheet 104 a to point 112 through core 106 (e.g., afoam or air core) via transversely extending pins 24 a and 24 b.Conventional plated through hole technology cannot be used with mostfoam core composites and thus pins 24 provide a suitable replacement toprovide pathways through the structure. And then, to provide electricalpathways in the planar direction of a composite structure, conductorsare integrated with the fabric of at least one ply thereof, e.g.,conductor 26 interwoven with the fabric of a ply of composite face sheet104 a. More than one ply may include conductive wires woven, knitted, orbraided with the fabric thereof, and the internal or external pliescould be chosen as desired to include pathways through the structure.Pins can be inserted through the thickness of a core, as discussed aboveand in U.S. Pat. No. 6,291,049 which is incorporated herein by thisreference, to reinforce the structure, to prevent delamination of theindividual plies with respect to each other, and to provide electricalpathways through the structure. In such an example, foam core 106, FIG.25 could be eliminated and there would simply be a number of compositefabric plies between face plate 104 a and face plate 104 b. Thus,aircraft wing notational antenna subsystem referred to in FIGS. 2-24above are but only a few examples of the wide variety of uses of theinnovative technology of the subject invention. Other uses include, butare not limited to, thermal conductivity and management, where pinsserve as thermal shunts to transfer heat, or pins 24 may be insertedthrough the thickness of the composite structure to provide sidewallmetallization around the cavity of a radiating element 36, as shown inFIG. 27.

Although specific features of the invention are shown in some drawingsand not in others, this is for convenience only as each feature may becombined with any or all of the other features in accordance with theinvention. The words “including”, “comprising”, “having”, and “with” asused herein are to be interpreted broadly and comprehensively and arenot limited to any physical interconnection. Moreover, any embodimentsdisclosed in the subject application are not to be taken as the onlypossible embodiments. Other embodiments will occur to those skilled inthe art and are within the following claims.

In addition, any amendment presented during the prosecution of thepatent application for this patent is not a disclaimer of any claimelement presented in the application as filed: those skilled in the artcannot reasonably be expected to draft a claim that would literallyencompass all possible equivalents, many equivalents will beunforeseeable at the time of the amendment and are beyond a fairinterpretation of what is to be surrendered (if anything), the rationaleunderlying the amendment may bear no more than a tangential relation tomany equivalents, and/or there are many other reasons the applicant cannot be expected to describe certain insubstantial substitutes for anyclaim element amended.

1. An electromechanical structure comprising: a core; a plurality ofconductive pins through the core; the pins configured to form a signaldistribution network from a first side of the core to a second side ofthe core.
 2. The structure of claim 1 in which there is an array ofradiating elements on the first side of the core each connected to oneend of a pin and a printed circuit board on a second side of the coreelectrically connected to the other ends of the pins forming a notionalantenna subsystem.
 3. The structure of claim 2 further including acomposite member comprising: plies of fabric, resin impregnating theplies of fabric, at least one ply including signal transmission elementsintegrated therewith and connected between the printed circuit board andelectronics for the notional antenna system.
 4. The structure of claim 3in which said core is a dielectric.
 5. The structure of claim 4 in whichthe dielectric core is air.
 6. The structure of claim 5 in which thedielectric core includes a dielectric support mechanism.
 7. Thestructure of claim 6 in which the dielectric support mechanism is adielectric honeycomb structure.
 8. The structure of claim 6 in which thedielectric support mechanism is a dielectric truss structure.
 9. Thestructure of claim 8 in which the truss structure includes a network ofdielectric pins forming the truss structure.
 10. The structure of claim4 in which the dielectric core is a low density material.
 11. Thestructure of claim 4 in which the dielectric core is foam.
 12. Thestructure of claim 4 in which the dielectric core is a polymer.
 13. Thestructure of claim 4 further including a radome layer over the radiatingelements.
 14. The structure of claim 13 in which the radome layer ismade of astroquartz.
 15. The structure of claim 2 further including aground plane between the core and the printed circuit board.
 16. Thestructure of claim 15 in which the ground plane is a composite layerincluding plies of conductive fibers impregnated with a resin.
 17. Thestructure of claim 16 in which the fibers are carbon.
 18. The structureof claim 15 further including a structural layer between the groundplane and the printed circuit board.
 19. The structure of claim 18 inwhich the structural layer includes a foam sub-layer on a compositesub-layer.
 20. The structure of claim 19 in which the compositesub-layer includes fibers impregnated with a resin.
 21. The structure ofclaim 20 in which the composite sub-layer fibers are carbon.
 22. Thestructure of claim 15 in which the ground plane includes holestherethrough for the conductive pins.
 23. The structure of claim 22 inwhich the conductive pins are insulated.
 24. The structure of claim 22in which the holes provide clearance between the conductive pins and theground plane.
 25. The structure of claim 1 in which the pins are solidand made of a metal alloy.
 26. The structure of claim 25 in which themetal alloy includes copper.
 27. The structure of claim 1 in which thepins include a composite core surrounded by metal coating.
 28. Thestructure of claim 1 in which the pins include a central conductorsurrounded by a dielectric material surrounded by a coaxial shieldconductor.
 29. The structure of claim 1 in which the pins are tubular.30. The structure of claim 1 in which the pins are configured to providesidewall metallization around a cavity of radiating element.
 31. Thestructure of claim 2 in which the radiating elements are printed on thecore.
 32. The structure of claim 2 in which the pins are insertedthrough holes drilled in the core.
 33. The structure of claim 30 inwhich the pins are first inserted through the holes formed in thedielectric core and the radiating elements are then printed over thepins.
 34. The structure of claim 3 in which the signal transmissionelements are wires woven into the at least one ply of the compositemember.
 35. The structure of claim 34 in which said wires are insulated.36. The structure of claim 1 in which the core is a solid compositecomponent made of a number of plies of fabric impregnated with a resin.37. An electromechanical structure comprising: a low density dielectriccore; an array of radiating elements one side of the core; a printedcircuit board on an opposing side of the core; and a plurality ofconductive pins through the core and insulated therefrom, the pinsconfigured to form a signal distribution network from the radiatingelements to the printed circuit board.
 38. A method of fabricating anelectromechanical structure, the method comprising: inserting aplurality of conductive pins through a core; and configuring the pins toform a signal distribution network from a first side of the core to asecond side of the core.
 39. The method of claim 38 in which there is anarray of radiating elements on the first side of the core each connectedto one end of a pin and a printed circuit board on a second side of thecore electrically connected to the other ends of the pins forming anotional antenna subsystem.
 40. The method of claim 39 further includinga composite member comprising: plies of fabric, resin impregnating theplies of fabric, at least one ply including signal transmission elementsintegrated therewith and connected between the printed circuit board andelectronics for the notional antenna system.
 41. The method of claim 39in which said core is a dielectric.
 42. The method of claim 41 in whichthe dielectric core is air.
 43. The method of claim 42 in which thedielectric core includes a dielectric support mechanism.
 44. The methodof claim 43 in which the dielectric support mechanism is a dielectrichoneycomb structure.
 45. The method of claim 43 in which the dielectricsupport mechanism is a dielectric truss structure.
 46. The method ofclaim 45 in which the truss structure includes a network of dielectricpins forming the truss structure.
 47. The method of claim 41 in whichthe dielectric core is a low density material.
 48. The method of claim41 in which the dielectric core is foam.
 49. The method of claim 41 inwhich the dielectric core is a honeycomb structure.
 50. The method ofclaim 39 further including disposing a radome layer over the radiatingelements.
 51. The method of claim 50 in which the radome layer is madeof astroquartz.
 52. The method of claim 39 further including disposing aground plane between the core and the printed circuit board.
 53. Themethod of claim 52 in which the ground plane is a composite layerincluding plies of conductive fibers impregnated with a resin.
 54. Themethod of claim 53 in which the fibers are carbon.
 55. The method ofclaim 52 further including disposing a structural layer between theground plane and the printed circuit board.
 56. The method of claim 55in which the structural layer includes a foam sub-layer on a compositesub-layer.
 57. The method of claim 56 in which the composite sub-layerincludes fibers impregnated with a resin.
 58. The method of claim 57 inwhich the composite sub-layer fibers are carbon.
 59. The method of claim52 in which the ground plane includes holes therethrough for theconductive pins.
 60. The method of claim 59 in which the conductive pinsare insulated.
 61. The method of claim 59 in which the holes provideclearance between the conductive pins and the ground plane.
 62. Themethod of claim 38 in which the pins are solid and made of a metalalloy.
 63. The method of claim 62 in which the metal alloy includescopper.
 64. The method of claim 38 in which the pins include a compositecore surrounded by metal coating.
 65. The method of claim 38 in whichthe pins include a central conductor surrounded by a compositedielectric material surrounded by a shield.
 66. The method of claim 38in which the pins are tubular.
 67. The method of claim 38 in which thepins are configured to provide sidewall metallization around a cavity ofa radiating element.
 68. The method of claim 39 further includingprinting the radiating elements on the core.
 69. The method of claim 39further including inserting the pins through holes drilled in the core.70. The method of claim 69 in which the pins are first inserted throughthe holes formed in the dielectric core and the radiating elements arethen printed over the pins.
 71. The method of claim 40 in which thesignal transmission elements are wires woven into the at least one plyof the composite member.
 72. The method of claim 71 in which said wiresare insulated.
 73. The method of claim 38 in which the core is a solidcomposite component made of a number of plies of fabric impregnated witha resin.
 74. A method of fabricating an electromechanical structure, themethod comprising: inserting a plurality of conductive pins through alow density dielectric core; insulating the pins from the low densitydielectric core and a ground plane; disposing an array of radiatingelements one side of the core; disposing a printed circuit board on anopposing side of the core; and configuring the pins to form a signaldistribution network from the radiating elements to the printed circuitboard.
 75. An electromechanical structure comprising: a core; aplurality of conductive pins through the core; the pins configured toform a signal distribution network from a first side of the core to aprinted circuit board on a second side of the core.
 76. The structure ofclaim 75 further including a ground plane between the core and theprinted circuit board.
 77. The structure of claim 76 in which the groundplane is a thin layer between the core and the printed circuit board.78. The structure of claim 77 in which the thin layer is copper.
 79. Thestructure of claim 77 in which the core is a dielectric core.
 80. Thestructure of claim 79 in which there is an array of radiating elementson the first side of the core each connected to one end of a pin. 81.The structure of claim 80 in which the printed circuit board iselectrically connected to the other ends of the pins forming a notionalantenna subsystem.
 82. The structure of claim 81 in which the notionalantenna subsystem is configured to be affixed to an aircraft panel. 83.The structure of claim 81 in which the dielectric core is air.
 84. Thestructure of claim 83 in which the dielectric core includes a dielectricsupport mechanism.
 85. The structure of claim 84 in which the dielectricsupport mechanism is a dielectric honeycomb structure.
 86. The structureof claim 84 in which the dielectric support mechanism is a dielectrictruss structure.
 87. The structure of claim 86 in which the trussstructure includes a network of dielectric pins forming the trussstructure.
 88. The structure of claim 81 in which the dielectric core isa low density material.
 89. The structure of claim 81 in which thedielectric core is foam.
 90. The structure of claim 81 in which thedielectric core is a polymer.
 91. The structure of claim 81 furtherincluding a radome layer over the radiating elements.
 92. The structureof claim 91 in which the radome layer is made of astroquartz.
 93. Thestructure of claim 77 in which the ground plane includes holestherethrough for the conductive pins.
 94. The structure of claim 77 inwhich the conductive pins are insulated.
 95. The structure of claim 93in which the holes provide clearance between the conductive pins and theground plane.
 96. The structure of claim 75 in which the pins are solidand made of a metal alloy.
 97. The structure of claim 96 in which themetal alloy includes copper.
 98. The structure of claim 75 in which thepins include a composite core surrounded by metal coating.
 99. Thestructure of claim 75 in which the pins include a central conductorsurrounded by a dielectric material surrounded by a coaxial shieldconductor.
 100. The structure of claim 75 in which the pins are tubular.101. The structure of claim 75 in which the pins are configured toprovide sidewall metallization around a cavity of radiating element.102. The structure of claim 81 in which the radiating elements areprinted on the core.
 103. The structure of claim 81 in which the pinsare inserted through holes drilled in the core.
 104. The structure ofclaim 103 in which the pins are first inserted through the holes formedin the dielectric core and the radiating elements are then printed overthe pins.
 105. A method of fabricating an electromechanical structure,the method comprising: pre-drilling pilot holes in a dielectric core;pre-forming pilot holes in a ground plane; pre-drilling holes in aprinted circuit board; and inserting a plurality of conductive pinsthrough each of the printed circuit board, the ground plane, and thedielectric core to bond together the dielectric core, ground plane andprinted circuit board.
 106. A method of fabricating an electromechanicalstructure, the method comprising: pre-drilling pilot holes in a groundplane attached to a printed circuit board; bonding the ground plane andprinted circuit board to a dielectric core; drilling holes through theprinted circuit board and dielectric core coinciding with thepre-drilled pilot holes in the ground plane; and inserting a pluralityof conductive pins through each of the printed circuit board, the groundplane, and the dielectric core.